Login via Face Detection

FOR GDM GDM LOGIN MANAGER

Add the PPA repository and Update

sudo apt-add-repository ppa:antonio.chiurazzi/ppa && sudo apt-get update

Install the Ubuntu Face Authentication / Face Recognition Library

sudo apt-get install pam-face-authentication

Tweak and Edit The System Now to add the face authentication module to GDM, Ubuntu's default login-manager:

sudo sed -i '1i auth sufficient pam_face_authentication.so enableX' /etc/pam.d/gdm 
sudo sed -i '1i auth sufficient pam_face_authentication.so enableX' /etc/pam.d/gnome-screensaver

Depending on your webcam model/make you may need to install and add libv4l to preload: Create the file /etc/ld.so.preload

Paste in the path to the v4l1compat.so file commonly found in /usr/lib/libv4l

Open "Face Trainer" (Application > Other), system will scan your face and add to database so that the system recognize your face while logi

Go to System > Administration > Users and Groups, change the password to Asked to login

Go to System > Administration > Login Screen, choose "Show the Screen for choosing who will log in", whis action will disable automatic login.

Done, you can logoff the system and test face authentication login in your ubuntu.

http://www.omgubuntu.co.uk/2010/09/login-to-ubuntu-using-your-face/

and

http://www.ubuntubuzz.com/2011/05/face-authentication-face-recognition.html

check these site you will get more info